Status of Detector Characterization a.k.a. Calibration & Monitoring Project Year 2 objectives ( → Mar ‘04) 1. Calibration plan (first draft in March ‘03 – still circulating…) 2. Define contents of calibration DB 3. Define algorithms 4. Monitoring interface for TestDAQ 5. Monitoring plan (new L4 for monitoring: Rodin Porrata) Manpower 1 FTE (UCB) FTE (UW) FTE (UD) + δ Kurt Woschnagg, UC Berkeley

Calibration Tasks Low-level calibrations: Timing7 ns Geometry1 m Charge, OM gain (lab, ice) Angular OM acceptance (lab) Optical ice properties High-level calibrations: Energy (cascades) Vertex resolution Pointing accuracy and angular resolution DOM lab calibrations not included here

Timing calibration Automatic, part of normal DAQ ops 1. Every waveform time-stamped (coarse, fine) locally in DOM 2. Clock calibration (RAPcal) to relate local times to global (master) time 3. PMT transit time measurement (in lab, in-situ with onboard LED) Testing (post-deployment): - with flasher data - with muons (req. reconstruction) Development and testing

Calibration devices Standard candles (lasers)vertex, energy Flasher boardsgeometry, timing, vertex, energy, ice Dust loggersice properties On-board LEDscharge, timing (transit time) Pressure sensorsgeometry, deployment Payout, drill, GPSgeometry Acoustic televiewerdrilling So far: physics requirements, cable issues

Geometry calibration in 3 stages ► Stage 1 (~days) Combine deployment data: surface survey, drill log, pressure data, payout etc. One shot! ► Stage 2 (~weeks → days?) Interstring calibration with flasher data Requires: timing calib. ► Stage 3 (~months → weeks → days?) Muon survey Requires: timing calib., reconstruction

Geometry calibration – Stage 1 Initial geometry from deployment data: GPS survey of surface locations Pressure sensors Drill log Well depth Cable payout + Hole diameter from acoustic televiewer → Absolute OM positions within ~1 m Time scale: days → day?

Geometry calibration – Stage 2 → Relative string positions within ~0.5 m Time scale: weeks → days? Global interstring fit to flasher timing data Does it work in IceCube?

Measuring ice flow with cosmic-ray muons Rigid down to 2000 m Stuck at bedrock Lagging 1.Reconstruct downgoing muon tracks 2.Find location for each OM that minimizes its contribution to the reconstruction likelihood

Geometry calibration – Stage 3 Survey with downgoing muons → OM positions within ~0.3 m Time scale: month(s) → weeks → days? Test: finds artificial shifts Development and testing on AMANDA data UCB (Jeff Allen, Dima)

Optical properties of ice So what is left to do… From in-situ light sources in AMANDA we get (after some analysis):

Optical properties in IceCube 1.Are the dust bands horizontal over km-scale? 2. What happens below 2100 m? 3. Can we measure hole ice prop.?

Calibration hardware Flasher boards Requirements document (ERD) finalized Each board has 12 LEDs (405 nm) 6 horizontal for geometry 6 at ~45° for cascade simulation All 12 can be fired independently Adjustable light output Cascade energies up to 10 TeV (at least)

Calibration hardware Dust loggers Conceptual design stage, but: Experience at UCB Proven method Optimal placement: in IceCube corners and at AMANDA center Deploy first season?

Record of Northern climate variations at GISP2 (Greenland Ice Sheet Project, 3054 meters) Dust in ice core Temperature record from ice core Dust logger data A dust logger in action Ryan Bay, UCB

DOM gain (charge) calibration Relate measured charge to number of photoelectrons In lab (pre-deployment): measured for all DOMs → database - SPE peak - linearity - dynamic range - saturation - dependence on HV, temperature In situ (post-deployment): on-board LED, min-bias muon data - SPE peak - linearity? saturation?

Calibration hardware On-board LEDs Hardware: Separate UV LED on DOM main board Purpose: Charge calibration: SPE peak Timing calibration: PMT transit time Work in progress Light output Pulse width Optical coupling Placement

Cascade energy calibration ~10 5 photons/GeV In-situ light sources: 1.Flashers; up to 10 TeV 2.Lasers; 1 TeV and up Standard candles: absolute calibration in lab Realistic cascade simulation (light distribution, timing) Overlay events to reach higher energies - saturation (database with lab measurements) - software

Getting ready for the first strings The first IceCube string is deployed in Dec ’04 …then what? Mainly calibrations in ’05 Timing calibration Reconstruction Deployment daq AMANDA/IceCube cross calibrations: - Common reconstruction - Coordinate system

Dependencies by WBS element Reconstruction Deployment DAQ AMANDA-IceCube integration Software Simulation In-ice devices (in-situ light sources) Monitoring, database, … help !